First Scratch-Built Tricopter

Formori

Beginner Crasher
Hey all,

I'm new to this forum (and rcgroups) but not new to RC! I've been playing with radio control cars and stuff most of my life, I currently have a Nitro T-maxx truck, an electric MiniRio boat (soon to be brushless!), a bunch of small coax heli's, and a SlowFly park flyer (mostly flown indoors). So since I find heli's in general to be pretty intimidating, but I'm slightly obsessed with the way they fly, I've decided to build and try my hand at multi-rotors!

Now, I have to start off with the reason for my choosing a tri over the many other formats and variations of multi's; that it's a platform I can understand the flying dynamics of, it's cheap and easy to build and strong and reliable enough that it can be learned on without too much damage when I crash it! Hence, I've gone with a modified rcexplorer design (like so many before me) and so far I quite like the design, reliability and cheapness of the whole project.

I'll be updating this build log as I go and probably posting my materials and parts list on this first post later when I have it all in place and I know what I've had to use, along with tips, trip-ups, and whatever I screw up as I go (cause it isn't fun if i don't swear at this thing at least once in a while when building and flying it, is it? ;)).

I started this project about 3 weeks ago, deciding on what design I wanted, which parts I needed, and my layout and general build plan. When that was all decided I made a (fairly large) hobbyking order, and picked up some other supplies locally and began the project.

I cut out my frame plates about a week ago from a template I based on David's design, but incorporated my own ideas, and cut out the arms and some coat-hanger wire landing gear. Then I built some ping-pong ball navigation lights that will go on the ends of the arms to let me know what direction my copter is at all times, and in keeping with my first design idea, I'm sticking with the KISS theory for this first build so I'll work around the copter as I go starting with tail, then left and finally right for all things that need to be different. Hence, my tail is red and it's a pull prop, Left is green and is a Pull, and finally Right is Blue (opposite of red) and is a pusher prop. This idea will help keep things simple as I decide to make changes/modifications to different systems.

Here's just the frame plates and arms screwed together with 4-40 temporary screws until I get my M3's in the parts order. You can see how I've changed from David's design and my arms are 45cm long from the CG point, but I might put the larger plate on top yet and mount an FPV camera upside down later on.
IMG_20120915_205158.jpg

And here's the folded out frame with training/crashing landing gear attached!
IMG_20120915_212406.jpg

And since I got my parts on Friday morning, it only makes sense that I started building today!

These are the plates I originally cut out of 3mm MDF hardboard, and have now soaked them in a laquer and wood penetrating bath that will strengthen and protect them. They're hung on fishing line to dry out and cure overnight.
Frame Plates Drying.jpg

While I wait for those to dry, it looks like there's a tricopter in this mess here somewhere...
Parts on my workbench.jpg

Now I have 3 arms done! Good work for a day, but I might have to rewire those ESC motor wires tomorrow, so I'll look at my plan tonight and try again tomorrow when I can actually put the plates in and assemble the frame.
Completed Arms.jpg

So now I'm up to date on this project, and since I killed most of my assignments this week I'll probably be back tomorrow for more work, if not I'll definitely be finishing the frame and basics on Monday and maybe a test fly next week!

Enjoy your thanksgiving weekend (those who are in Canada with me), everyone else just enjoy your weekend!

~Formori~
 

Formori

Beginner Crasher
Oh, and if anyone is wondering why it looks like I'm building on a school worktable, it's because I am! I'm a member of OhmBase Hackerspace in Thunder Bay, ON, and I'm using the lab's workstations to complete this while I'm away from home attending school (my own home workbench is 4000kms away :().

If anyone has any questions about the project, or questions about the hackerspace (or hacklabs in general), or just comments on my build feel free to comment or msg!

Enjoy!

~Formori~
 

colorex

Rotor Riot!
Mentor
Awesome, I get flashbacks of my own tricopter build :)

I use 4-40 screws with no problem... just a few grams extra weight.
 

Formori

Beginner Crasher
Building on Thanksgiving!

Okay, so I didn't get to the hackerspace yesterday, with homework and Thanksgiving things on the go, so today I spent almost all day there getting work done!

So here's what I've got done now:

Here's a test fit of the arms on the finished frame plates, all assembled finally!
Frame and Arms Test Fit Folded.jpg

Here's my magical FC and Rx protecting box, the Soapbox!
My Soapbox FC Protector.jpg

Everything is wired inside the soapbox and fits quite nicely in there.
Soapbox FC and Rx Connected and ON.jpg

Here's the battery harness I wired up that goes between the frame plates and still allows for enough room to swing the left and right arms back and fold the tricopter up.
Wiring Battery Harness 2.jpg

Here's wiring the tricopter and attaching everything to the arms and frame.
Wiring Battery Harness.jpg

Here's all of the wiring done and I turned on the FC and Rx!!! Now to setup the KK2.0 board and configure everything.
Frame FC and Rx All Connected.jpg

Here's the (mostly) completed tricopter, and I actually hovered it for a few seconds in the room!!!
Completed Tricopter.jpg

Now I just can't wait to get the remaining stuff done and get out flying with her!

Oh, yeah, the remaining "to do's", ugh...
I still need to:
- Properly balance my props, motors, and then dynamically balance everything.
- Cut off the excess axles on the motors and clean up the cut-off portions on the frame plate bolts.
- Finish assembling and install my Navigation lights (both LED balls and the strip under the tail).
- Move the landing gear out more on the arms, and probably change them (they're really, really springy).
- Remount and center-up tail servo (it's waaaay off center from what it should be, and it's affecting my yaw range).
- Mount LiPo more securely with second strap.
- etc. (I'll probably think of more before I get back to it)

I hope you all had a good Thankgiving weekend in Canada, or a good Columbus Day in the US, or whatever holiday from wherever you're from! I'll be back as soon as I can manage more time to work on this thing!

Enjoy!

~Formori~
 

Formori

Beginner Crasher
So I went for my first flight yesterday!!!

I had some time yesterday and went into the workshop to finish the few things with the tri as it is, after trimming the motor axles and cleaning up a few things (while waiting for batteries to charge) I went out and took off from the abandoned football field next door.

She's a little shaky, and I know I need to fix up my PI gains, but she flies well and hovers at just under half throttle!

In this process tho, I managed to break the cheap digital servo I bought for the tail, so I need to replace it now. I have an analog one on there at the moment but it always seems to be all over the place (doesn't stay straight up as I increase throttle).

I'm going to change the rate on the KK board the next chance I get to work on her, but does anyone else know if there's anything else I should do to try and help the tri's stability?

Hopefully will be flying again soon!
 

Formori

Beginner Crasher
Sorry I haven't posted in a while, school got busy with midterms, but I have managed to get her off the ground and for a good few flights!

Tricopter Flight 2012.10.20.jpg

I've still got some work to do, and some more pictures to take and post, but I promise I'll be back soon!